package com.duan.blog.config;

import com.duan.blog.common.CustomException;
import com.duan.blog.common.RespUtil;
import com.duan.blog.constants.CodeEnum;
import lombok.extern.slf4j.Slf4j;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

@Slf4j
public class JWTFilter extends BasicHttpAuthenticationFilter {
    /**
     * 判断用户是否想登录
     */
    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        HttpServletRequest req = (HttpServletRequest) request;
        String token = req.getHeader("token");
        return token != null;
    }

    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest req = (HttpServletRequest) request;
        String token = req.getHeader("token");
        if(token == null || token.isEmpty()){
            throw new CustomException(CodeEnum.TOKEN_ERROR);
        }
        JWTToken jwtToken = new JWTToken(token);
        //提交给realm进行登入，如果错误他会抛出异常并被捕获
        getSubject(request, response).login(jwtToken);

        return true;
    }

    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
        if(isLoginAttempt(request, response)){
            try{
                executeLogin(request, response);
                return true;
            }catch (Exception e){
                e.printStackTrace();
                return responseError(response);
            }
        }
        return true;
    }

    /**
     * 对跨域提供支持
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }


    /**
     * 将非法请求跳转到 /unauthorized/**
     */
    private boolean responseError(ServletResponse response ) {

        response.setCharacterEncoding("UTF-8");
        response.setContentType("application/json; charset=utf-8");
        try (PrintWriter writer = response.getWriter()) {
            writer.print(RespUtil.fail(CodeEnum.TOKEN_ERROR));

        } catch (IOException e) {
            log.error("response error", e);
        }
        return false;

    }
}
